A new method for pyrrole peri-annulation: synthesis of 1H-1,5,7-triazacyclopenta[c,d]phenalenes from 1H-perimidines

New methods for the synthesis of 1H-1,5,7-triazacyclopenta[c,d]phenalenes have been developed based on a sequence involving Schmidt reaction of keto-perimidines and acylation of the intermediate amides with 1,3,5-triazines or carboxylic acids. The same synthetic sequence starting from the corresponding alkylperimidine includes acylation with acetic acid as the first step.